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Title: PATHOGENESIS OF O157:H7 ESCHERICHIA COLI INFECTION IN NEONATAL CALVES

Author
item Nystrom, Evelyn
item Bosworth, Brad
item MOON, HARLEY - USDA, ARS, PIADC

Submitted to: Rushmore Conference on Mechanisms in Pathogenesis of Enteric Diseases
Publication Type: Proceedings
Publication Acceptance Date: 9/28/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Cattle have been implicated as an important reservoir of Shiga-like toxin- producing Escherichia coli (E. coli) (SLTEC) O157:H7, enterohemorrhagic E. coli (EHEC) that cause hemorrhagic colitis and hemorrhagic uremic syndrome in humans. Naturally- or experimentally-infected cattle can shed low levels of E. coli O157:H7 long-term, but little is known about the pathogenesis of E. coli O157:H7 infection in cattle. E. coli O157:H7 induce characteristic attaching and effacing (A/E) mucosal lesions in ceca and colons of 1-day-old gnotobiotic piglets and this model is used to study the pathogenesis of SLTEC infections. A/E lesions were not detected in histologic sections of the intestines from adult cattle or 3- to 14-week- old calves infected with E. coli O157:H7. Our objective was to determine if E. coli O157:H7 induce A/E lesions in neonatal calves. Colostrum- deprived calves (< 12-h-old) were bottle-fed with antibiotic-free milk replacer containing 10**10 CFU of O157:H7 (SLT-I**+, SLT-II**+) or nonpathogenic E. coli, necropsied 18 h postinfection and their intestines examined histologically. Bacterial attachment, effacement of microvillous borders, and destruction of epithelium were observed in the intestines of the neonatal calves inoculated with E. coli O157:H7. No lesions were observed in calves inoculated with nonpathogenic E. coli. The distribution of intestinal lesions in neonatal calves resembled that in gnotobiotic pigs. Neonatal calves are apparently more susceptible to A/E lesions induced by E. coli O157:H7 than are older calves or adult cattle and provide a model for studying the pathogenesis of E. coli O157:H7 infections in cattle.